The present invention relates generally to stringed instruments, and in particular to a stringed instrument soundboard and soundbox.
Stringed instruments generally fall into two major categories: those with solid bodies requiring a magnetic pick-up mounted under the strings to amplify the strings vibrations, and those that achieve amplification through, a hollow resonating cavity. The present invention relates to the latter.
Stringed instruments are divided into three main parts: the hollow body; the neck, which holds the frets; and the head, which contains the tuning pegs.
The soundboard is a wooden piece mounted on the front of the body, used to amplify the instrument sound. One or more generally large holes cut into the soundboard enhances sound transmission. For example, guitars generally have a round hole which may or may not be centered, while violins have a f-shaped pair of holes. The face of the neck is called the fingerboard or fret board and is separated into sections by dividers called frets. The frets are comprised generally of metal pieces mounted such that when a string is pressed down onto the fret, the length of the vibrating string is effectively changed, thereby allowing for control of the pitch and articulation of the music being played.
At the top of the fret board between the neck and the head is the nut. The nut is generally grooved to accept the string as it passes onto the head portion to wind into the tuning peg. As the tuning peg is turned, tightening the string, the tension on the string increases making the string""s pitch higher. Conversely, loosening the string, which decreases the tension, lowers the pitch.
A bridge is attached to the soundboard for anchoring the other end of the string. A thin hard piece embedded into the bridge is called the saddle. It is upon the saddle that the strings rest. As the strings vibrate, the vibrations pass through the saddle to the bridge and into the soundboard, causing the entire soundboard to vibrate. The body of the stringed instrument forms a hollow soundbox, thereby amplifying the vibrations of the soundboard.
The body of most stringed instruments has a narrowing or xe2x80x9cwaistxe2x80x9d forming two widened areas on either side of the waist, called bouts. The neck connects to the upper bout and the bridge attaches to the lower bout. It is the size and shape of the body and the bouts that produces the tone of a given stringed instrument. In general, the lower bout accentuates lower tones and the upper bout accentuates higher tones.
The challenge in building a stringed instrument is that the soundboard must be light in weight and flexible enough to vibrate freely, yet strong enough to withstand the tension of the strings. If the soundboard is too heavy, it will produce a muffled tone, if it is too delicate, the instrument will not be durable. Most luthiers have been willing to sacrifice some clarity of tone to make a long lasting instrument.
Current practice utilizes bracing to add strength to the soundboard without dampening too much of the soundboard""s vibration. Bracing plays a major role in determining the tone of a stringed instrument, as well as aiding in the efficient propagation of the vibrations through a large area of the soundboard. Scalloped bracing is a method wherein wood is selectively removed from predetermined areas of the braces. In this manner, the bracing of the soundboard is weakened enough to allow it to vibrate freely without being so weak so as to make it structurally unsound. In longitudinal cross-section, a scalloped brace is generally in the form of a suspension bridge. Scalloped bracing is generally suitable for medium gauge or lighter strings only.
A second form of current practice bracing is known as X-bracing, shown in FIG. 1.
With X-bracing, the two main braces 2 under the soundboard 4 run in an xe2x80x9cXxe2x80x9d from the upper bout 6 to the lower bout 8. Generally, the xe2x80x9cXxe2x80x9d crosses at a predetermined location between the sound hole 10 and the bridge not shown). There may be auxiliary bracing 12 other than the main X-bracing. In some stringed instruments, the location of the X crossing 14 is placed such that the bridge rests more or less directly on the main X-braces, known as high-X-bracing, advanced X-bracing, or pre-war bracing. In this manner, the bridge can transfer more of its vibration to the soundboard 4. High X-bracing is usually scalloped.
Attempts have been made at producing a relatively thin soundboard while maintaining adequate strength. For example, U.S. Pat. No. 5,379,444 to Borisoff is directed to a bridge device for a stringed musical instrument comprising a bridge plate mounted adjacent to a front surface of the body of the musical instrument, a plurality of saddles secured to the bridge plate, and a plurality of armatures pivotally secured to the bridge plate. The bridge plate is secured to a bridge mounting block located substantially interiorly of the guitar, extending through a hole cut into the soundboard without touching the soundboard. To further secure the bridge mounting block, a truss rod engages a neck block and the bridge mounting block. A turn buckle allows for variation in truss rod length. Rotating the turn buckle results in increased guitar body tension to. counter-act the increased tension of the strings. In this manner, the bridge plate is mounted to the stringed instrument independent of the soundboard.
U.S. Pat. No. 6,040,510 to Yaun is directed to tensioned, springs attached to hooks which are disposed within the soundbox of a stringed musical instrument. A wood block is affixed to the inside top surface of an upper sounding board directly under and substantially parallel to a saddle. Two conventional eye-hooks are screwed into the block. Two oppositely spaced bottom blocks are affixed to the inside bottom surface at the neck of the soundbox and one eye-hook is screwed into each of the bottom blocks. Two springs are tensionally displaced within the soundbox in a V-shaped configuration by attachment to the eye-hooks.
U.S. Pat. No. 5,058,479 to Shaw is directed to a collapsible guitar in which the interior of the body is reinforced by a combination of truss rods and an adjustable brace member to retain optimum alignment within the body itself and between the body and wing panels. A cable or wire runs diagonally from the lower edge of the inside wall rearward and upwardly to the forward end of downwardly directed channels permanently attached to the underside of the top panel and end wall.
Although current practice has produced acceptable results, what is needed are improved methods to stretch a thin soundboard across a frame, keeping the weight away from the area that needs to vibrate, without muffling the tone. The present invention fulfills this need and further provides related advantages.
The present invention provides for a stringed instrument wherein a generally thin soundboard is stretched across a frame, keeping the weight away from the soundboard area that needs to vibrate, without muffling the tone. In a preferred form, a neck, or neck extension, reaches substantially through the body of the instrument. A block is anchored to the neck in close proximity to where the neck enters the body. The soundboard is attached securely to this block. Near the opposite end, a floating block is fastened securely to the soundboard. The neck is cut to an effective length to push against the floating block and act as fulcrum. At least one rod is anchored to the neck near the end where the neck enters the body and an opposite, threaded, rod end is inserted through holes near the bottom of the floating block to receive threaded nuts. Tightening the nuts effectively shortens the rod length, pulling the floating block back towards the end where the neck enters the body. In this manner, the floating block acts as a lever, stretching the soundboard.
In a second form, the neck extension and anchored block are omitted. Two floating blocks are fastened securely to the soundboard. A fulcrum block is cut to an effective length and fitted snugly between the two floating blocks near, but without contacting, the soundboard. At least one rod is passed through holes near the bottom of the floating blocks, the rod threaded at both ends to receive a nut. The length of the fulcrum block, and hence, the distance between the two floating blocks is such that when either or both nuts are tightened, the floating blocks are tilted slightly, stretching the soundboard and keeping the soundboard in tension.
One advantage of the present invention is that the sustained tone produced by the stringed instrument increases because of the increased tension on the soundboard, allowing the soundboard to vibrate more easily.
Another advantage is that the soundboard can be made thinner, with increased stiffness, producing enhanced vibration, and hence, louder, clearer tone, without increasing the weight of the instrument.
Yet another advantage of the present invention is that the tension placed on the soundboard prevents; without the need for bracing, soundboard cracking and warping associated with temperature and humidity changes.
Still another advantage is that the increased tension to the soundboard created by the present invention reduces the movement of the bridge, resulting in less variation in pitch and, allows the soundboard to vibrate more easily, thereby increasing the sustained tone.